<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ page  import="java.io.*,java.util.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<%
	//获取session创建时间
	Date createTime=new Date(session.getCreationTime());
	// 获取最后访问页面的时间
	Date lastAccessTime = new Date(session.getLastAccessedTime()); 
	
	String title = "session的例子";
	Integer visitCount = new Integer(0);
    String visitCountKey = new String("visitCount");
    String userIDKey = "userID";
    String userID = "ABCD";

    // 检测网页是否由新的访问用户
    if (session.isNew()){
		title = "设置 session";
		// map.put(key,value)
		session.setAttribute(userIDKey, userID);
		session.setAttribute(visitCountKey,  visitCount);
    } else {
	   title = "获取 session";
	   visitCount = (Integer)session.getAttribute(visitCountKey);
	   if(visitCount==null) {session.setAttribute(visitCountKey,0); visitCount=0;}
	   visitCount += 1;
	   userID = (String)session.getAttribute(userIDKey);
	   session.setAttribute(visitCountKey,  visitCount);
   }
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h1>Session跟踪</h1>
	<table border="1" align="center"> 
<tr bgcolor="#949494">
   <th>Session 信息</th>
   <th>值</th>
</tr> 
<tr>
   <td>id</td>
   <td><% out.print( session.getId()); %></td>
</tr> 
<tr>
   <td>创建时间</td>
   <td><% out.print(createTime); %></td>
</tr> 
<tr>
   <td>最后访问时间</td>
   <td><% out.print(lastAccessTime); %></td>
</tr> 
<tr>
   <td>用户 ID</td>
   <td><% out.print(userID); %></td>
</tr> 
<tr>
   <td>访问次数</td>
   <td><% out.print(visitCount); %></td>
</tr> 

<%
 Enumeration headerNames =session.getAttributeNames() ;
 while(headerNames.hasMoreElements() ){
	
	 String paramName = (String)headerNames.nextElement();
     out.print("<tr><td> +" + paramName + "</td>\n");
     String paramValue = session.getAttribute(paramName).toString();
     out.println("<td> " + paramValue + "</td></tr>\n");
}
%>
</table> 
</body>
</html>